Process for chlorinating polymeric materials



Patented July 3', 1945 PROCESS FOR CHLOB INATING POLYMERIC MATERIALS Reginald George Robert Bacon and William John Roy Evans, Manchester, England, assignors to Imperial Chemical Industries Limited, a corporation of Great Britain No Drawing. Application 400,462. In Great This invention relates to the manufacture of chlorinated polymeric materials and more particularly to the chlorination of polyvinyl chloride.

It has already beenv proposed to chlorinate auction of highly chlorinated materials with use- June 30, 1941, Serial No.

Britain July 3, 1940 9 Claims. (or. 204-163) ful physical properties, but smaller or greater proportions may be used as desired or the chlorination may be effected in the absence of solvents and swelling agents.

As examples of our improved process for prepolymerised vinyl chloride by acting with chlo- One method of carrying out the invention is to mm in a solution or suspension of the polymer pass chlorine into the aqueous suspension of the in a solvent or in a swelling agent for instance in polymerised vinyl chloride at a convenientrate carbon tetrachloride or in tetrachloroethane. until the desired degree of chlorination has been Working according to this proposal, however, inefiected. Interaction between the chlorine and volves using large quantities of organic liquids of 10 the polymer may be accelerated by operating which there is always a certain loss. Further, if under suitable physical conditions. For instance polymerised vinyl chloride, which is to be chlothe chlorination is usually efiected at least in the rinated is obtained by the convenient process of later stages at elevated temperature, for example polymerising vinyl chloride in an aqueou emul- 70-100 C. with vigorous agitationof the reacsion, it is necessary to isolate the polymer prior to N tion medium, andoit is often advantageous for its chlorination. This isolation involves manua proportion of a solvent or swelling agent or facturing steps such as the coagulation of the both to be'present and for the reaction medium dispersion, washing and drying. to be strongly illuminated. Further, as a large We have now found that the chlorination of quantity of hydrogen chloride'is'liberated during polyvinyl chloride can be carried out efi'ectively 90 the chlorination it isusually preferable to incorby passing chlorine into an aqueous medium con-, porate with the reaction medium small propo'rtaining the polyvinyl chloride in suspension. Soltions of dispersing or emulsifying agents which vents and swelling agents for the polyvinyl chloare capable of rendering dispersions or emulsions ride may also be present, singly or in admixture stable in acid media, so that the tendency of the and the reaction zone may be exposed to actmic polymer to coagulate inthe presence of acidic radiation. b materials is overcome. Suitable emulsifying and Accordingly one of the objects of this invention dispersing agents are, for example, the sodium is to provide a process for the production of chlosalt of sulphated sperm oi] alcohols and sulrinated polyvinyl chloride by which the utilisation phonated oleic acid. During the chlorination 'the of large quantities of organic liquids with the atpolymer remains in suspension or if a solvent or tendant loss of solvent may be avoided. Further a swelling agent is present remains suspended in objects of the invention will become apparent in the aqueous phase in'a dissolved or swollen state. the ensuing description. When the chlorination has been effected, excess The invention may be applied to polyvinyl of chlorine may be removed by air-or nitrogenchloride obtained in any known manner. It is blowing the reaction medium after which the solparticularly applicable, however, to polyvinyl vent or swelling agent may be removed by distilchloride obtained in aqueous emulsion by mainlation with or withoutsteam and at atmospheric taining an aqueous emulsion of monomeric vinyl or reduced pressure, or the water may be rechloride, which may contain other ingredients moved by adding an organic solvent for the poly such as emulsifying, dispersing or buffering mer and distilling the mixture under such conagents, polymerisation catalysts or plasticisers, ditions that the water is removed and a lacquer at a suitable pressure and temperature until the solution remains. If no'solvent or swelling agent desired degree of polymerisation has been atis used, the product is usually isolated from the tained, since such emulsions may be further chloaqueous medium by filtration. Alternatively the rinated without isolating the polyvinyl chloride. chlorinated polymer may be isolated by mixing Suitable solvents or swelling agents for the the reaction medium with a coagulating liquid polymers, which maybe added'to the aqueous sussuch as ethanol. The products are conveniently pensionsin proportions as high for example as dried at a slightly elevated temperature for ex- 16 parts to one part of the polymer are the chlo-j ample 40 to C., and at atmospheric or reduced rinated hydrocarbons such as ethylene dichlopressure. ride or tetrachloroethane. In general, however, The products are useful, especially in the form the solvents and swelling agents are used in small of solutions in organic liquids, for the production amounts, for example 8 parts to one part of the of films or other shapes and as ingredients of polymer is usually suiilcient for the rapid pro- 66 coating compositions.-

' persing agent and polymerisation catalyst.

I ised vinyl chloride, prepared 2 paring chlorinated polyvinyl chloride the following may be given but they are not intended to v limit the scope oi the invention, all parts being by weight.

Example I chloride was precipitated in fibrous form. Thisproduct was removed by filtration washed with ethanol and dried. It had a chlorine content of and a relative viscosity of 13.3 as No. 2 Ostwald viscometer using a 2 per cent solution in tetrachloroethane at C.

was prepared by agitating in 45 C. a mixture of vinyl chloride, water, a disdispersion contained 22 per cent polyvinyl chloride with a chlorine content of 54.9 per cent and with a K value of 62.9, as measured by the procedure described in British specification No. 485,- 000.

Example If 114 parts of the aqueous dispersion of polymerised vinyl chloride prepared'as described in Example I, were diluted with 137 parts of water. The mixture was illuminated with an electric lamp (500 watts) and stirred at a temperature of 50-60 C. and chlorine was passed in at the rate oi 15 parts per hour for 5 hours. The chlorinated polymer was then removed by filtration, washed with water and dried when it was found to have a chlorine con nt of 59 per cent.

Example 111 120 parts of an-aqueous dispersion of polymeras described'in Example I and containing 25 parts of the polymer, were mixed with 102 parts of water containing 2.5 parts of the sodium salt of sulphated sperm oil aicohols, and 315 parts of ethylene dichloride. The liquid was stirred at a temperature of 80 C., illuminated with a 500 watt electric lamp and chlorine was passed in at the rate of 20 parts per hour for 12 hours. The chlorinated polymer was isolated as described in Example I and contained 63.3 per cent chlorine and had a relative viscosity of 11.2, as measured in a No. 2 Ostwald viscometer using a 2 per cent solution in tetrachloroethane at 20 C.

Example 1v An aqueousdispersion of polyvinyl chloride was prepared and chlorinated as in Example 1, except that 120 parts of tetrachloroethane were used. The chlorination was effected at 80 C. and the chlorinated polymer was isolated by blowing steam into the reaction liquid, cooling and filtering. The chlorinated polymer had a chlorine content of 60.4 per cent and was more soluble in tetrachioroethane orethyl acetate than the original polyvinyl chloride. but it was not sumcientiy soluble to form a mobile solution therein at 20 C.

16 mm: an aqueous was stirred and asvaeoo Example V 114 parts in an aqueous dispersion of polymerised vinyl chloride prepared as described in l!- containing 25 parts of the polymer were mixed with 400 parts 0! tetrachloroethane. Chlorine was passed into the mixture at the rate of 15 parts per hour for 5 hours, whilst it was stirred and maintained at C. and illuminated with a 00 watt electric lamp. The chlorinated polymer was isolated by adding the emulsion so obtained, in a thin stream to 1000 parts of ethyl alcohol and ilitering. The product had a chlone content of 65.6 per cent by weight and a relative viscosity of 6.7 (as measured in a No. 2 Ostwald viscometer using a 2 per cent solution by weight in tetrachloroethane at 20 C.

Example VI 100 parts'oi an aqueous dispersion containing 23 parts of polyvinyl chloride and a small amount of a dispersing agent (sulphatedmethyl oleate) were diluted with 60 parts of water. The mixture was heated to approximately 100 C. and gaseous chlorine was passed in while the mass V illuminated by a 500 watt lamp. During the first half hour a certain amount of iroth was formed b..t this disappeared and a somewhat coarse precipitate was formed in the liquid. Chlorination was continued for 39% hours at the same temperature and with continued stirring when the solid produce was filtered oil washed with water and dried. The product was a readily soluble chlorinated polyvinyl chloride containing 68.5% 01:.

Emarnple vn I 100 parts of an aqueous dispersion containing 23 parts of polyvinyl chloride and a small amount of a dispersing agent (sulphated methyl oleate) were diluted with 60 parts of water. The mixture was stirred gently, illuminated by a 500 watt lamp and heated to 38 C. while chlorine was passed into the mass. Alter one hour precipitation started .lnd the temperature was raised to between and C. and was maintained there for a further cblorinating period c! 19% hours. No trouble with frothing was encountered and the solid product, after filtering, washing with water and drying, was readily-soluble chlorinated polyvinyl chloride containing 67.0 per cent Ch.

As various changes might be made in our process without departing from the spirit of our invention, that invention should not be restricted to precise details and conditions, except as necessitated by the appended claims.

We claim:

1. The process for producing a. chlorinated polymer oi vinyl chloride which comprises preparing an aqueous dispersion of p ly inyl chloride and chlorine into said aqueous dispersion in the presence of actinic radiation until the desired degree of chlorination is obtained.

2. The process for producing a chlorinated polymer of vinyl chloride which comprises preparing an aqueous dispersion of polyvinyl chloride containing a dispersins agent capable o! maintaining said dispersion in the presence of hydrochloric acid, and chlorine into said aqueous dispersion in the presence of actinic radiation until the desired degree of chlorination isobtalned.

' 3. The process for producing a chlorinated polymer 01 vinyl chloride which comprises predispcrsion of polyvinyl chloride and a chlorinated hydrocarbon which has a solvent action on polyvinyl chloride in the proportion of not more than about 16 parts by weight of said chlorinated hydrocarbon to each part by weight of polyvinyl chloride, and passing chlorine into said aqueous dispersion in the presence of actinic radiation until the desired degree of chlorination is obtained.

4. The process polymer of vinyl chloride which comprises preparing an aqueous dispersion of polyvinyl chlo- 5. The process for producing a chlorinated polymer of vinyl chloride which comprises preparing an aqueous dispersion of polyvinyl chloride and tetrachlo'rethane acid, and passing chlorine into said aqueous dispersion in the pres- .ence of actinic radiation until the desired degree agent capable of maintaining said dispersion in the presence of for producing a chlorinated in the proportion of chlorine into said aqueous dispersion in the presence o1 actinic radiation until the desired degree 01' chlorination is dbtained.

7. The process for producing a chlorinated 5 polymer of vinyl chloride which comprises preparing an aqueous dispersion of polyvinyl chloride and a chlorinated hydrocarbonwhich has a solvent action on polyvinyl chloride in the proportion 01' not more than-about 16 parts by weight 01' said chlorinated hydrocarbon to-eaoh part by weight of polyvinyl chloride, said dispersion containing as dispersing agent the sodium salt of sulphated sperm oil alcohols, and passing chlorine into said aqueous dispersion in the presence 01' actinic radiation until the desired degree of chicrination is obtained.

8. The process for producing a chlorinated polymer of vinyl chloride which comprises preparing an aqueous dispersion of polyvinyl chloride and tetrachlorethane in the proportion of not more than about chlorethane for each 16 parts by weight of tetrapart by weight of polyvinyl chloride, said dispersion containing as dispersingagent the sodiumsalt of sulphated sperm 011- alcohols, and passing chlorine into said aqueous dispersion in the presence of actinic radiation until the desired degree of chlorination is ob- I tained.

9. The process for producing a chlorinated polymer of vinyl chloride which comprises preparing an aqueous dispersion oi" polyvinyl chloride and ethylene dichloride in the proportion of not more than about 16 parts by weight of ethylene dichloride for each part by weight of polyvinyl chloride, said dispersion containing as dispersing agent the sodium salt of sulphated sperm oil alcohols, and passing chlorine into said aqueous dispersion in the presence of actinic radiation until the desired degree of chlorination is obtained.

REGINALD GEORGE ROBERT BACON. WILLIAM JOHN ROY EVANS. 

